The circum-Mediterranean spider genus Dysdera has undergone an outsanding species radiation in the volcanic archipelago of the Canary Islands. The present study deals with the endemic species that inhabit the older and ecologically distinct islands of Fuerteventura, Lanzarote and their nearby islets. A new species, Dysdera sanborondon, is described. The male of D. spinidorsum Wunderlich 1991, is described for the first time. Five species are redescribed: D. alegranzaensis Wunderlich 1991; D. lancerotensis Simon 1907; D. longa Wunderlich 1991; D. nesiotes Simon 1907, and D. spinidorsum Wunderlich 1991. The species D. liostethus Simon 1907 is proposed to be a senior synonym of D. clavisetae Wunderlich 1991 and its presence in the eastern islands is considered to be doubtful. A neotype is designated for D. nesiotes. The distribution of D. alegranzaensis is extended to Lanzarote and the other northern islets. Dysdera nesiotes is reported for the first time in the eastern Canaries. Morphological affinities and distribution patterns are discussed. The remarkably lower number of endemic species harbored by the eastern islands, when compared with other Canarian islands similar in size but younger in age, is proposed to be the result of a major extinction event in the eastern Canaries due to climatic change.